Risk Assessment Of Trace Elements Research Articles

Ecological and health risk assessment of trace elements in surface soil in an arid region of Xin Jiang, China

Trace element pollution in soil has become an increasingly common issue and potentially harms the environment and human health. In this study, the contamination levels and ecological and health risk indices of trace elements in surface soils in Bai Cheng, Xin Jiang, were investigated in order to examine if the land usage changed from pasture to agriculture has influenced the behaviours of these trace elements. In this study, descriptive analysis, normality test, the Tukey-HSD method and non-parametric methods were used to investigate the characteristics of trace elements. The geo-accumulation pollution and ecological risk indices were used to analyse the degree of contamination by trace elements. Correlation and principle analyses were used to identify the sources of trace elements and a health risk assessment was used to analyse human exposure to trace elements of the soil. Cadmium was the main pollutant in the 0–5 cm soil layer in both agricultural and pastoral areas. Thus, it contributed most to the Geo-Accumulation Index (Igeo) and the comprehensive potential ecological risk index (RI) of the surface soils. The levels of RI for the topsoil layer of agricultural areas fell into moderate to high (II-III) ecological risk categories, and those of pastoral areas belonged to low to moderate risk categories (I-II). Both values of Igeo and RI of the surface soils in agricultural areas were higher than in pastoral areas. The carcinogenic risk of Cr through hand-to-mouth intake and the total risk of trace elements in soils for humans were higher than the safety reference level. Chromium was the greatest contributor to total carcinogenic risk. Trace element concentration levels in surface soils in pastoral areas were relevant to geochemical characteristics and atmospheric deposition, whereas trace element concentration levels in surface soils in agricultural areas were derived not only from geochemical characteristics but also from human activities. The change in land use from pasture to agriculture increased the trace element concentration level in surface soils. There were both ecological risks and human health implications for residents exposed to such contaminants of soils in the studied region.

Investigation and probabilistic health risk assessment of trace elements in good sale lip cosmetics crawled by Python from Chinese e-commerce market

A growing body of evidence suggests that the lip products are polluted by heavy metals, which would inevitably cause safety problems with long-term exposure, but few studies have focused on their deeper health risk assessments. This study sets out to identify the lip cosmetics in good sale from Chinese e-commerce market utilizing Python crawler and then explore the probabilistic health risks caused by 6 trace elements in 34 most popular lip cosmetics with Monte Carlo simulation. The results found that there was no obvious non-carcinogenic risk to humans. As for high users, the carcinogenic risk levels of Cr exceeded the acceptable risk recommended by USEPA, approximately 10% and 25% for lipsticks and lip glosses, respectively. Cr was regarded as the priority metal for risk control in the present study. Finally, it was recommended that the minimum use period limit for using up one lip product ranged from 0.54 months to 5.74 months. Overall, this study appears to be the first to conduct a probabilistic health risk assessment of trace elements in lip products, which would be of significance for policy makers to take effective strategies to minimize exposure health risk and contamination.

Health risk assessment of trace elements of ambient PM2.5 under monsoon patterns

In order to identify the contribution to health risk derived from various emission sources, this study investigated monsoon variations in PM2.5 mass and concentrations of the associated trace elements in a region with complex pollution sources in central Taiwan. This study applied the Chemical Mass Balance model to analyze the source contribution of PM2.5. The source apportionment to obtain the risk contribution of different sources were conducted for different monsoon periods according to the monsoon patterns. In this way, the contributions of individual sources and chemicals to health risk under different monsoon types can be understood to support development of effective control strategies. Among the top contributors of PM2.5 during the north-east monsoon were Secondary Aerosol 28.93% >Coal Boiler 19.82% >Crustal Dust 15.99%; in south-west monsoon were Coal Boiler 37.29% >Traffic Emission 21.19% >Secondary Aerosol 17.84%. The total risk of cancer was above the acceptable risk (3.07 × 10−6), while the non-carcinogenic risk was within the acceptable range (0.262). The variation in the concentration and composition of PM2.5 was related to the change of monsoon type. During the north-east monsoon, the air mass had a long transmission distance and the PM2.5 concentration was relatively high. During the south-west monsoon, the air mass had a short transmission distance and the composition was mainly influenced by nearby emission sources, which resulted in higher risk due to chemical characteristics. To provide sound air quality management, attention should be paid to the composition of PM2.5 in addition to its concentration.

The concentration and health risk assessment of trace elements in commercial soft drinks from Iran marketed

ABSTRACT The aim of the present study was to assess the concentration of the trace elements Al, As, Cd, Ba, Cr, Cu, Hg, Ni, Pb, Mn, Fe and Zn in 150 commercial soft drinks marketed of Iran, using inductive couple plasma–optical emission spectroscopy (ICP-OES). The data obtained were compared with the permissible limit set for drinking water by the Codex Alimantarius (CA), United States Environmental Protection Agency (USEPA), Food and Agriculture Organization/World Health Organization (FAO/WHO) and National Standard of Iran (NSI). The highest mean level was 84.11 ± 27.06 μg/L is related to Fe and the lowest was <detection limit to As and Hg. The concentrations of Pb, Ni, Cr, Cu, Ba, Hg, Cd and As in samples were lower than the limit set by USEPA, FAO/WHO, CA and NSI. In contrast, the concentrations of Fe, Al, Mn and Zn soft drink samples were higher than the limit set by USEPA, FAO/WHO, CA and NSI. Monte Carlo simulation results indicated that the trend of potential non-carcinogenic risks in all samples was Cd > Cr > Pb > Ni > Al > Ba. Target hazard quotient index of toxic elements, for adults and children, was considerably lower than the safe risk limits THQ > 1.

Source identification of soil elements and risk assessment of trace elements under different land uses on the Loess Plateau, China.

To investigate the source identification of soil elements and risk assessment of trace elements under different land-use types, 32 pairs of topsoil samples (0-20cm) were collected from two subcatchments in the Liudaogou watershed. The areas of the two subcatchments were 0.343 and 0.045km2, respectively, and the two subcatchments were divided into four land-use types, including bare land, forestland (FL), grassland (GL) and check-dam land (CDL). The results showed that the coefficients of variations of all soil elements indicated moderate spatial variation. The mean concentrations of Cu, K, Mn, Na and Zn under different land-use types exceeded the soil background values. The results of correlation analysis and principal component analysis illustrated that high homology existed between Cu and Mn in subcatchment 1, and the main source was from coal mines and smelters. Consistent sources of Zn and K in subcatchment 1 were mainly fertilizers and sewage sludge. Cu, K, Mg, Mn, Na and Zn in subcatchment 2 had similar sources, mainly mining and smelting plants, fertilizers and sewage. In addition, Ca had high homology with Fe in two subcatchments, mainly from natural weathering. The enrichment factor values indicated that there was a certain degree of trace element pollution. The values of the pollution index and Nemerow integrated pollution index revealed that moderate pollution was mainly concentrated in FL, GL and CDL. The trace element pollution of GL and CDL may induce contamination of the food chain and threaten human health safety.

Health risk assessment of trace elements through exposure of particulate matter-10 during the cooking of Ethiopian traditional dish sauces

This study was aimed to analyze trace elements in the particulate matter-10 and evaluate their health risks during the cooking of the most widely consumed Ethiopian traditional dish sauces (Wots) using charcoal, kerosene and electricity stoves. The trace elements (iron, cadmium, arsenic, chromium, lead, boron, nickel, cobalt, tin, copper and zinc) in the particulate matter-10 were found in the range 0.001–0.175 µg m−3. The human health risk assessment has done based on the United States Environmental Protection Agency prescription. The hazard quotient and hazard index values using charcoal, kerosene and electricity stoves were found below 1. This result showed that the inhabitants stay at any of these three microenvironments has no likelihood to have non-cancer health problems. In addition, the life time cancer values for all trace elements were below the tolerable range set by United States Environmental Protection Agency, except chromium, cadmium and arsenic which were found within the tolerable range. Furthermore, the total sum of eleven determined elements was calculated, and the highest concentration was observed using kerosene stove followed by charcoal and electricity stoves, respectively. The use of kerosene and charcoal stove were not the recommended stove as compared to electricity stove for the cooking of Wot.

Contamination identification, source apportionment and health risk assessment of trace elements at different fractions of atmospheric particles at iron and steelmaking areas in China.

China has the largest share of global iron and steel production, which is considered to play a significant contribution to air pollution. This study aims to investigate trace element contamination at different fractions of particulate matter (PM) at industrial areas in China. Three PM fractions, PM2.1-9.0, PM1.1-2.1 and PM1.1, were collected from areas surrounding iron and steelmaking plants at Kunming, Wuhan, Nanjing and Ningbo in China. Multiple trace elements and their bioavailability, as well as Pb isotopic compositions, were analysed for identification of contaminants, health risk assessment and source apportionment. Results showed that PM particles in the sites near industrial areas were associated with a range of toxic trace elements, specifically As, Cr(VI), Cd and Mn, and posed significant health risks to humans. The isotopic Pb compositions identified that coal and high temperature metallurgical processes in the steelmaking process were the dominant contributors to local air pollution in these sites. In addition to iron and steelmaking activities, traffic emissions and remote pollution also played a contributing role in PM contamination, confirmed by the differences of Pb isotopic compositions at each PM fraction and statistical results from Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE) and Geometrical Analysis for Interactive Aid (GAIA). The results presented in this study provide a comprehensive understanding of PM emissions at iron and steelmaking areas, which helps to guide subsequent updates of air pollution control guidelines to efficiently minimise environmental footprint and ensure long term sustainability of the industries.

Food Supplements for Weight Loss: Risk Assessment of Selected Impurities.

Nowadays, food supplements are widely consumed, often without any medical supervision. In this study, 25 food supplements for weight loss, randomly purchased from five different suppliers in the European Union, were analysed by Wavelength Dispersive X ray Fluorescence spectrometry (WDXRF). The aim of this study was the risk assessment of trace elements and the mixture of elements present in food supplements for weight loss. The obtained Hazard Index (0.11) showed no potential risk of non-carcinogenic effects to human health. However, since humans are frequently exposed by different routes and/or sources to toxic metals, the additional consumption of these products may cause potential toxicological risks that cannot be ignored. In one analysed food supplement (FS), the simultaneous presence of Pb and Mn in high concentrations was detected. In two, FS chromium concentrations were above the reference daily dose. Unconformities were detected between the labelled and the detected values, which emphasises the misinformation of labels. This highlights the need for a deeper surveillance of food supplements.

Geochemical behaviour and risk assessment of trace elements in a tropical river, Northwest Borneo

By convention, dissolved trace elements in the river water are considered to be the fraction that passes through a 0.45 μm filter. However, several researchers have considered filtration cut-off other than 0.45 μm for the separation of dissolved trace elements from particulate fraction. Recent research indicated that trace elements could exist in particulate form as colloids and natural nanoparticles. Moreover, the trace elements in the continental dust (aerosols) constitute a significant component in their geochemical cycling. Due to their high mobility, the trace elements in the micron and sub-micron scale have biogeochemical significance in the coastal zone. In this context, this study focuses on the highly mobile fraction of trace elements in particulates (<11 μm) and dissolved form in the Lower Baram River. A factor model utilizing trace elements in the dissolved and mobile phase in the particulates (<11 μm) along with water column characteristics and the partition coefficient (Kd) of the trace elements indicated a more significant role for manganese oxyhydroxides in trace element transport. Perhaps, iron oxyhydroxides play a secondary role. The factor model further illustrated the dissolution of aluminium and authigenic clay formation. Except for Fe and Al, the contamination risk of mobile trace elements in particulates (<11 μm) together with dissolved form are within the permissible limits of the Malaysian water quality standards during monsoon (MON) and postmonsoon (POM) seasons.

Chemical fractionation and risk assessment of trace elements in sewage sludge generated from various states of Pakistan.

In the developing world, rapid urbanization and industrialization produces an enormous volume of wastes daily. This study was aimed to explore the potential and risks associated with sewage sludge through the characterization and fractionation technique. Sewage sludge samples were collected from various wastewater treatment in five different cities of Pakistan. Considerable amounts of macro-elements were detected in all types of sewage sludge samples. The pHw of all sewage sludge were neutral to slightly alkaline in reaction. Total organic carbon (TOC) was maximum (18.73%) with Coca-Cola sewage sludge (CSS) while the minimum (14.69%) was with Water and Sanitation Agency (WASA) sewage sludge (WSS). Percent relative distribution of cadmium (Cd) was higher in residual fraction (F4) up to 52% in the Nestle wastewater treatment plant, Sheikhupura (NSS). The chromium (Cr) concentration in Kasur sewage sludge (KSS) was extremely in mobile fraction (exchangeable) as compared with all other sludge samples, therefore showing a higher level of risk assessment code. While in the case of Iron (Fe), mobility was less and its maximum portion was noted in residual fraction (F4) of all sewage sludge samples. Percent distribution of manganese (Mn) showed variable trends for different sewage sludge samples. Zinc (Zn) concentration showed high mobility (exchangeable fraction) in case of NUST wastewater treatment plant, Islamabad (NTS) (31.16%) and WSS (37.83%) as compared with other sewage sludges. The risk assessment code indicated that Zn and Ni had a medium level of risk with I-9 Sector wastewater treatment plant, Islamabad (ISS), CSS, KSS, and NSS whereas these pose a high risk with NTS and WSS. Based on physicochemical properties, nutrients, trace elements, mobility, and risk assessment code, it was concluded that KSS should not be recommended at any application rate while NTS and WSS may be used at low application rates whereas ISS, CSS, and NSS may be used for agricultural crop production.

English

English

Contamination zoning and health risk assessment of trace elements in groundwater through geostatistical modelling.

Trace elements (TEs) concentration in groundwater is a key factor for health risk assessment (HRA). To achieve high level of accuracy in HRA, the present study performed Monte Carlo simulations, sensitivity analysis and uncertainty analysis to a total of 184 (N=184) groundwater samples, collected during December 2016 from Birbhum district. TEs in samples were detected by anodic stripping voltammetry (ASV). The mean concentration of TEs were found as Fe (855.88μg/L)> Zn (204.0μg/L)> Cu(84.9μg/L)> Ni(47.31μg/L)> Pb(14.43μg/L)> Co(10.58μg/L)> Cd (7.88μg/L). It indicated serious contamination by Fe, Cd. Pb and Ni according BIS, 2012. Pollution indicators such as heavy metal pollution index (HPI) revealed that study area is heavily contaminated by these TEs. Incremental lifetime cancer risk (ILCR) value of TEs showed that Cd is the main offender for cancer risk. Average value of total hazard index (THI), was found to be 2.48. THI through ingestion pathways was found to be more risky than dermal contacts accounting for 88% and 12% health hazard respectively. The sensitivity analysis indicated ingestion rate, exposure time, and TEs concentration were the most influential parameters for all groundwater associated health hazards. The TEs affected areas were mapped through Empirical Bayesian Kriging geostatistical model and health risk prone zones were projected. The study demonstrated that Monte Carlo simulation and EBK can provide better accuracy in health risks prediction and spatial distribution analysis of contaminants in any geographical area. The TEs and their hazard zonation mapping with geostatistical modelling will be helpful for the policy makers and researchers to improve groundwater quality management practices.

Human health risk assessment of trace elements in drinking tap water in Zahedan city, Iran.

Daily intake of elements through the consumption of drinking water, due to its detrimental effects, is accounted for an important concern. Although the health risk assessment of heavy metals in different water sources has extensively carried out in various studies, the effect of age and the concentration of all trace elements in drinking tap water have neglected. Therefore, this study was conducted to evaluate the concentrations of heavy metals, e.g., As, Cd, Cr, Ni, Pb, B, Al, Hg, Mn, Zn, Cu, Fe, Se and Ba in the drinking tap water of Zahedan city and to estimate their non-carcinogenic and carcinogenic effects. Moreover, this is the first research in Iran that has also been dedicated to complete investigation on daily intakes of trace elements in tap water. A total of 155 samples of drinking water were randomly taken from the tap water and were analyzed using ICP-OES device. The estimation of the carcinogenic and non-carcinogenic risks of analyzed elements was carried out based on the guidelines of the U.S EPA. The hazard index (HI) values for children and adult age groups were 9.84E-01 and 4.22E-01, respectively. The cumulative Excess Lifetime Cancer Risk (ELCR) for carcinogenic trace elements was in range of tolerable carcinogenic risk 10-6 to10-4 and for all carcinogenic elements were in the order of Pb > Cd > Cr. It also detected that the total carcinogenic risks of the Cd, As and Cr in water samples through the ingestion route are at the levels of "low risk" and "low-medium risk".

Ecotoxicological characteristics and ecological risk assessment of trace elements in the bottom sediments of the Rożnów reservoir (Poland).

The bottom sediments in catchment areas behind dams play a significant role in water ecosystems. On the other hand, the structure of sediments makes them a natural geosorbent, in which pollutants introduced to the aquatic environment accumulate. The use of biotests is recognised as an important approach for the assessment of the quality of bottom sediments, as the chemical analysis of sediment samples alone does not provide evidence of the impact of contaminants on biota. The aim of the study was to apply the chemical and ecological indices to determine the potential risk posed by trace elements in the bottom sediments and to evaluate sediment toxicity using organisms belonging to two taxonomic groups, i.e., plants (Phytotoxkit) and crustaceans (Rapidtoxkit). The 46 sediment samples were taken from the Rożnów Dam Reservoir in Southern Poland. The mean concentration of the trace elements in the sediments was 5.22 mg As; 0.26 mg Cd; 63.23 mg Cr; 28.65 mg Cu; 37.11 mg Ni; 11.15 mg Pb; 69.69 mg Zn and 0.09 mg Hg ∙ kg-1 d.m. The mean probable effect concentration quotient (PECq) value among different sampling sites ranged between 0.04 and 0.33 suggested moderate potential toxicity to the biological communities in bottom sediments. The Ni was potentially the most toxic element for biota in the Rożnów Reservoir. The sensitivity of organisms formed the following order: Thamnocephalus platyurus >Lepidium sativum >Sinapis alba >Sorghum saccharatum. For the plants, the stimulating effect of bottom sediments on root growth was often indicated, while a toxic effect was demonstrated for T. platyurus in 80% of the samples. However, the correlation analysis and PCA results showed that trace elements that originated from similar sources were associated to the toxicity of sediments towards T. platyurus, while ecotoxicity for plants could not be explained by the content of trace elements in bottom sediments. T. platyurus is a good indicator for predicting the toxicity of bottom sediments from the Rożnów Reservoir. However, our study found that both chemical and ecotoxicological analyses are important for a comprehensive evaluation of the quality of bottom sediments.

Study of Cd Content Distribution and Its Bioaccessibility in Edible Tissues of Crab Portunus trituberculatus from the Coastal Area of Shandong, China.

Bioaccessibility study is of great significance to the health risk assessment of trace elements in the seafood. In this work, the most consumed crab (Portunus trituberculatus) in coastal area of Shandong, China was analyzed to study the distribution and the bioaccessibility of cadmium (Cd) in the edible tissues of crab, and the dietary risk from consumption of crab was also evaluated. Results showed that the content of Cd in the whole edible tissues of 109 crab specimens ranged from 0.052 to 8.89 mg/kg ww (wet weight) with mean of 2.26 mg/kg ww. The Cd content in 85% of the crab samples was higher than the national food safety limits (0.5 mg/kg ww) of China. The gender study indicated that there was no significant difference in Cd content in total edible tissues between the males and females (p > 0.05). Cadmium was highly concentrated in the brown meat with mean value of 4.13 mg/kg ww, which was about 5 times higher than that in the white meat (0.75 mg/kg ww). The bioaccessibility of Cd ranged from 48.1 to 71.0% in the white and brown meat. The risk assessment based on the bioaccessibility of Cd revealed that the consumption of the edible crab brown and white meat for adults should be limited in 0.13 kg and 1.56 kg per week respectively.

Geochemical fractionation and risk assessment of trace elements in sediments from tide-dominated Hooghly (Ganges) River Estuary, India

The geochemical fractionation and potential mobilization of cadmium, chromium, copper, nickel and lead were studied in surficial sediments (top 0–10 cm; <63 μm grain-size) of the Hooghly (Ganges) River Estuary, eastern part of India, using a sequential extraction procedure. The risk assessment was evaluated at three specific levels; i.e., enrichment level (enrichment factor, geo-accumulation index), the availability level (elements bound to different fractions, risk assessment code, Individual and Global contamination factors) and biological toxicity level (Potential ecological risk index; sediment quality guidelines). Different geochemical phases indicated heterogeneities in TE distribution patterns as follows: (i) Cd was dominant in the exchangeable phase and significant proportion of Pb was bounded to the reducible fractions; (ii) the potential mobile fraction (ΣF1 − F3) in the sediments was higher for Cd and Pb (>46%), reflecting their adverse impact on benthic organisms as they are weakly bound to the sediment and can migrate to water; (iii) a minor fraction of Cu (<10%) was found in the oxidizable fraction suggesting less environmental risk to the aquatic biota and (iv) the dominance of the Ni, Cr and Cu in the residual fraction supports the assumption of their geogenic origin. Both Cd and Cu posed medium to high ecological risk values based on risk assessment code (RAC). Global Contamination Factor (GCF) values allowed to identify the “pollution hotspots” in the study area.

Source apportionment and health risk assessment of trace elements in the heavy industry areas of Tangshan, China

Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure 20 trace elements in PM2.5 from the Tangshan heavy industry areas. The variation characteristics, potential sources, and health risks of these trace elements were analyzed in great detail within the research area. The results showed that the annual total concentration of the 20 elements in the research area did not change significantly from 2016 to 2017, and the contributions of Na, Mg, Al, K, Ca, and Fe were very high, accounting for 89–96% of the total concentration. The concentrations of these elements were higher during the day than they were at night, and the concentrations in the spring and winter were higher than they were in the summer and autumn. Five potential sources were identified using the positive matrix factorization (PMF) model and enrichment factors (EFs). Traffic, dust source, oil combustion, coal combustion, and industrial sources contributed 17.80%, 12.2%, 8.8%, 7.7%, and 53.5% to the total trace elements, respectively. The contribution of each source was significantly different during different seasons. Industrial sources including steel industry and cement production were the largest source; nearly 70% of the total trace elements in the winter of 2017 were from industrial sources. The health risk assessment reflected that the cancer risks of Cr, Ni, and Cd to adults, and Cr to children were higher than the acceptable levels (1 × 10−6). Furthermore, Mn had a potential non-carcinogenic risk to children and adults, which should be given more attention by relevant departments.

Carcinogenic and non-carcinogenic risk assessment of trace elements and POPs in honey from Shirak and Syunik regions of Armenia

Honey is a highly nutritious natural product widely produced and consumed by people in Shirak and Syunik regions of Armenia. Unlike Shirak, Syunik is under the impact of mining industry. Since the environmental pollution can adversely impact the safety of honey and entail a probable risk to human health, it is important to evaluate the presence of potentially toxic trace elements in honey samples from both regions and draw comparisons. This study assesses the dietary exposure to trace elements and persistent organic pollutants through the intake of honey for the first time among people in Shirak and Syunik regions. 24-hour dietary recall method was used to investigate the consumption of honey. The presence of seven trace elements (Pb, Cd, As, Hg, Cu, Zn, and Ni) and persistent organic pollutants (hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT) and its metabolites) were determined in honey samples using atomic absorption spectrometry and gas chromatography-mass spectrometry, respectively. In several samples, the concentrations of Cu were above the maximum allowable level. Non-carcinogenic risk values did not exceed the acceptable level, while carcinogenic risk values for Ni and As exceeded the risk level of 10−6 in both regions. Moreover, among the persistent organic pollutants, only the concentration of DDT in honey from Shirak was above the European Union maximum residue level.

Spatial distribution, contamination levels, sources, and potential health risk assessment of trace elements in street dusts of Urumqi city, NW China

A total of 83 dust samples were collected from the streets of Urumqi city in NW China and analyzed for the concentrations of As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn elements. The spatial distribution, contamination levels, main sources, and potential health risks of these trace elements were determined based on geostatistical analysis, geo-accumulation index, multivariate analysis, and the health risk assessment model introduced by the USEPA, respectively. The obtained results indicate that the average concentrations of Cd, Cr, Cu, Hg, Ni, Pb, and Zn exceed the corresponding background values determined in Xinjiang soils by factors of 2.0, 1.35, 1.38, 8.24, 1.28, 2.09, and 3.26, respectively. The spatial distribution patterns of the nine trace elements in street dust were found to be substantially heterogeneous, and the contamination level decreased in the following order: Hg > Zn > Pb > Cd > Cr > Cu > As > Ni > Mn. Based on the identified concentrations, the collected dust samples were found to be moderately polluted by Hg, and not polluted by As, Cr, Cu, Mn, and Ni. The remaining elements, Cd, Pb, and Zn lie on the borderline between non-pollution and moderate pollution levels. Furthermore, it was shown that Mn and Zn in street dusts originate from both, natural and anthropogenic sources, while As, Cd, Cr, Cu, Hg, Ni, and Pb are mainly produced by anthropogenic sources. Overall, the carcinogenic and non-carcinogenic health risks of the analyzed elements, instigated primarily by oral ingestion of street dusts, were found to be within the acceptable range for both, children and adults. As and Cr are the main non-carcinogenic elements, whereas Cr is the major carcinogenic element among the investigated dust-bound metals in the study area.

Oral bioaccessibility and human health risk assessment of trace elements in agricultural soils impacted by acid mine drainage

Cultivated soils around the historic mine site of Tharsis (Spain) contain elevated concentrations of As (up to 621 mg kg−1), Cu (752 mg kg−1) and Pb (2395 mg kg−1), exceeding the regional background levels and the statutory limits set for agricultural use. A site-specific health risk assessment of occupational and environmental exposures was conducted using an approach based on guidelines from regulatory agencies, refined by combining bioaccessibility and bioavailability data.Oral bioaccessibility, as determined by simulating the human digestion process in vitro (Unified BARGE Method), was largely related to total trace element concentrations in soil. Arsenic seemed to be evenly distributed among the gastric and gastro-intestinal phases (about 31%), whereas the bioaccessible fraction of pH-dependent metal cations, like Pb and Zn, was noticeably higher in the stomach (nearly 50%) than in the gastro-intestinal tract (less than 10%). Bioaccessibility assessed by single extraction with 0.43 M HNO3 was overestimated by a factor of 1.2–1.4 relative to that obtained from the BARGE method.Site-specific relative bioavailability (RBA) values of As (27.7%) and Pb (42.6%), predicted from bioaccessibility measurements through linear regression models, had little effect on the overall risk estimates. For the ingestion pathway, the RBA-adjusted cancer risk values (9.7E-05 to 2.0E-04) exceeded the regulatory threshold in all plots, and the hazard index re-calculated after adjustment of oral dose was also above the allowable limit, with values ranging from 2.5 to 4.8. However, no detrimental health effects are expected to occur through inhalation of soil particles in nearby residents.